Method of and apparatus for stirring materials



April 2l, 1936 w. w. KAGI 2,038,221

METHOD OF AND APPARATUS FOR STIRRING MATERIALS Filed Jan. l0, 1955 W W /fAG/ Patented Apr. 21, '1936 METHOD F AND APPARATUS FOR STIRRING MATERIALS Walter W. Kagi, La Grange, Ill., assigner to Western Electric Company, Incorporated, New York, N. Y., a corporation of New York Application January 10, 1935, Serial No. 1,120

6 Claims.

'I'his invention relates to a method of and apparatus for stirring materials, and more particularly to a method of and apparatus for mixing lead alloys.

Although not limited thereto, the method and apparatus of the present invention are particularly applicable for mixing lead alloys for cable sheath. Such sheath is, in some instances, made from lead alloyed with a hardening constituent, such as calcium or antimony, the amount of which must be maintained within close limits in order to produce uniform cable sheath having the desired characteristics. Also, the hardeningl constituent must be thoroughly and intimately mixed with the lead.

Such alloys are usually prepared in a large melting receptacle or kettle in which a mechanical stirrer or agitator is. employed for thoroughly mixing the calcium or antimony with the lead.

' With mixing apparatus heretofore employed it has been exceeding dimcult'to prevent agitation of the dross or oxide containing surface of the molten alloy in the kettle with the resulting contamination of the alloy and losses of the hardening constituent, especially when calcium is employed.

An object of the present invention is to provide an improved method of and` apparatus for elllciently and economically stirring and/or mixing materials.

In accordance with the above object, there is provided in one embodiment of the invention an improved mixing apparatus for lead alloys, comprising a melting receptacle or kettle within which a stationary horizontal baille member is axially positioned below the surface of the molten alloy in the kettle. A stationary open-ended tube or cylinder is positioned below the baille member and concentric therewith, the upper end of the tube being spaced from the lowersurface of the baille member and the lower end of the tube being spaced above the bottom of the kettle. A mechanical stirrer or mixer positioned axially within the tube is designed to cause a circulation of the alloy upwardly through the tube and against the under surface of the submerged stationary baffle member, which deflects the upwardly propelled stream of molten alloy downwardly, exteriorly of the tube, and thereby prevents agitation of the dross containing surface of the molten alloy.

A more complete understanding of the invention will be had from the following detailed description when read in conjunction with the accompanying drawingwhich shows a vertical (Cl. 26S-34) section of a mixing apparatus embodying the features of the invention.

As shown in the drawing, a lead melting and mixing receptacle or kettle I0 is provided at the bottom with the usual discharge opening I I con- 6 trolled by a valvev I2carried by a vertical shaft I3 adapted to be connected to suitable mechanism (not shown) for opening and closing the valve. The kettle is open atv the top to permit charging it with lead and other ingredients, such 10 as calcium or antimony, which are `melted with the lead by the application of heat to the kettle;

Mounted within the kettle I 0 concentrically thereof is a stationary horizontal baille member I5 in the form of a circular plate of vadiameter 15 considerably smaller than-the inside diameter of the kettle. This baille plate is positioned-an appreciable distance below the top of the kettle and the molten alloy in the kettle is constantly. maintained at such a level that the baille plate is 20 at al1-times wholly submerged below the surface of the molten alloy. A stationary vertical tube or cylinder is mounted below the baille plate and concentric therewith, the lower end of the'cylinder being suitably spaced above the bottom of 25 the kettle while the upper end of the cylinder is suitably spaced below the under surface of the baffle plate.

The baille plate and the cylinder are rigidly supported by vertical rods I1 secured to and depending from a cross bar I8 attached to the top of the kettle. Secured to the upper side of the cross bar I8 is a bracket I9 formed with a bearing portion 20 in axial alignment with the baille platey and cylinder. A vertical shaft 2| is ro- 35 tatably journaled in the bearing 20 and extends through aligned aperturesvin the cross bar and baille plate into the cylinder, terminating near the lower end of the cylinder. One or more helical blades 24 secured to the lower end of the 40 shaft 2i serve to circulate the molten materials in the kettle when the shaft is rotated by suitable means connected to the upper end thereof (not shown). The blades 24 are designed to pro-f pel a continuous stream of the moltenmaterials ,45 upwardly through the cylinder and against the stationary baille plate I5, the under surface 25 of which is flared or curved so as to deflect the stream of material downwardly and exteriorly of the cylinder. The materials are thereby thor- 50 oughly mixed without ag-itating or disturbing the oxide or dross containing surface layer A the alloy above the stationary baille plate.

It is to be understood that the invention is not limited to. the particular embodiment thereof I substantially undisturbed.

2. A method of stirring a molten metal, which comprises maintaining a body of metal in a molten'condition, causing a portion of said metal to flow upwardly from near the bottom of said body to near the upper surface thereof, deiiecting said upwardly flowing metal before it reaches the upper surface of said body and causing it to flow downwardly, and maintaining the upper surface of said body substantially undisturbed.

3. In a mixing apparatus, a receptacle for materials to be mixed, and means for circulating the materials to mix them, said means including a stationary horizontal baille member submerged below the surface of the materials for preventing agitation of the surface layer of the materials.

4. In a mixing apparatus, a receptacle for materials to be mixed, means for propelling upwardly a stream of the materials within said receptacle, and a stationary horizontal bafiie member submerged below the surface of the materlal for deilecting said stream downwardly to prevent agitation of the surface layer of the materials.

5. In an apparatus for stirring molten metal,

a receptacle for molten metal, a vertical tubular member centrally positioned within said receptacle below the surface of the metal, means for propelling a stream of the metal upwardly through said tubular member, and a stationary horizontal baille member positioned above said tubular member and below the surface of the metal for Y'deecting said stream downwardly and exteriorly of said tubular member to prevent said stream from disturbing the surfacey of the metal in any substantial manner.

6. In an apparatus for stirring molten metal, a receptacle for molten metal, a vertical tubular member centrally positioned within said receptacle with its upper end spaced below the surface of the molten metal and its lower end spaced above the bottom of said receptacle, rotary means within said tubular member for propelling a 

